There's a website that has to do with this topic, it's ran by someone who lived it HollywoodHangover.com It's not very organized, but you can easily spend a few hours checking out all the people, connections & where are they now.

The key impact of both crimes is that Conspiracy to Commit Murder and Felony Murder do not require the defendant to actually kill anyone or even be present when someone is murdered to be guilty of murder. That, of course, rather obviously is directed at Charles Manson.